Part 3 (1/2)

V

QUALIFICATIONS OF AN AIRPLANE MECHANIC

What chance has a good automobile man who knows his engine thoroughly to become an airplane mechanic? There can be only one answer to this question which men ask themselves daily--there is every chance in the world. Commercial flying, in the day when the air is to become a medium of transportation, just as ground and water are at present, must draw to itself hundreds of thousands of mechanics. The only thing to which the future of flying may be compared is the automobile industry at present. And the only place from which the mechanics are to be recruited are from the men who are working in garages putting automobiles in order.

An interesting comparison between the future for the automobile mechanic or airplane mechanic compared with the future for the pilot is afforded in the figures of a well-known flying-officer of great vision. He expects that the skilled mechanic, the man who has spent years at his trade, will command more for his services than a pilot.

Any one can learn to fly an airplane in one or two months of proper training. A mechanic may work for years to learn his profession.

It was estimated that it took ten mechanics of various kinds on the ground to keep one airplane pilot flying in the air, and the experience of the United States has shown that there must be a large force of trained men to keep up flying. The present leaders of the automobile world and the aeronautical world are men who got their first interest in mechanics in some little shop. Glenn H. Curtiss and Harry G. Hawker, the Australian pilot, both owned little bicycle-repair shops before they saw their opportunity in flying.

Most essential of all, for the man who would become an airplane mechanic, is a thorough knowledge of gasolene-engines. This should include not only a knowledge of such fundamentals as the theory of the internal-combustion engine, carburetion, compression, ignition, and explosion, but also a keen insight into the whims of the human, and terribly inhuman, thing--the gasolene-motor. Nothing can be sweeter when it is sweet, and nothing more devilish when it is cranky, than an airplane engine.

There are certain technical details which distinguish an airplane motor from an automobile motor, but a man who knows automobile engines can master the airplane motor in short order. Generally speaking, the airplane motor differs from the automobile motor in shape. The Liberty type of engine is V-shaped, with both sets of cylinders driving toward a common center, the crankshaft. Most airplane motors have special carbureters, and their oiling systems are extremely finely adjusted to take up any friction at their high speed. They will be found to be lighter in weight, with pistons, piston heads and other parts made of aluminium. They are, as a rule, more carefully made than most automobile motors, with especial attention to the fitting of all working parts.

One advantage which an airplane mechanic has is standardization, which has reached a high point with Liberty, Hispano-Suiza, and Curtiss engines. Once a mechanic has learned his type he has learned practically every engine of that type. For a long time to come the 18,000 Liberty engines which this country had at the time the armistice was signed will be carrying commercial airplanes across broad stretches of the United States. If it had not been for the pressure of the war this engine might have been developed slowly, as the automobile engines were, with changes from year to year. The Liberty engine has reached a high standard of efficiency, and is likely to be the standard airplane engine in this country for several years to come. An airplane mechanic who knows his Liberty engine will be able to look after most of the airplanes with which he will come into contact.

An engine which was not developed to the same high point in this country as the Liberty motor is the rotary engine, of which the Gnome Monosoupape or Clerget are perhaps the best-known types. These were favorites with airmen flying fighting scout-planes. They weighed practically nothing, for an engine. A one-hundred-horse-power motor weighed only two hundred and sixty pounds, and it was a splendid type for fast work. Briefly, the power generated by the explosions in the cylinders, operating against two centers of pressure, gave a rotary motion to the cylinders and crankcase, revolving around a stationary, hollow crankshaft. Cylinders and crankcase were bolted together, and the cylinders looked like the blades of an electric fan. There was always an odd number of cylinders, so that there would be no dead-centers, no point at which two opposing strains would be balanced, causing the engine to stop. The propeller was bolted on a nose cap which revolved with the engine. This type of engine is not likely to be used to any extent for commercial flying, or even flying for sport. It is expensive, very wasteful of gasolene and oil, and difficult to keep in repair.

For men who may have had some experience in the a.s.sembly of airplanes at factories, or of rigging them at flying-fields, there is great opportunity. Expert riggers who know their craft are few and hard to get. They are invaluable for maintaining a machine in flying condition. The use of airplanes in this country will require men for rigging, for truing up the wires and struts. Each airplane must be overhauled after a few hours of flight to discover hidden weaknesses and to tighten sagging wires.

Rigging an airplane has some resemblance to rigging a s.h.i.+p for sailing. The first requisite is to see that the machine is properly balanced in flying position. There is a number of minute measurements which come with the blue-print of every machine and which must be followed out to the letter to get the most successful results. An important detail is the pitch of the planes, or the angle of incidence, as it is called. This is the angle which a plane makes with the air in the direction of its motion. Too great a pitch will slow up the machine by offering too great a resistance to the air; too small an angle will not generate enough lift. The tail plane must be attached with special care for its position. Its angle of incidence must exactly balance the plane, and it must be bolted on so that there is no chance of it cracking off under strain.

Radio operators will be in great demand for flying. Brig.-Gen. A.C.

Critchley, the youngest general officer in the British service, who was a pilot in the Royal Air Force, said that the future development of the airplane must go hand in hand with the development of wireless communication. He added that the most difficult thing about flying, especially ocean flying, was to keep the course in heavy weather.

There are no factors which will help a man on ”dead” reckoning; and a s.h.i.+ft in wind, unknown to the navigator of a plane, will carry him hundreds of miles from his objective. The wireless telephone was used to some extent during the war for communication between the ground and the air; it will be used to a greater extent in the next few years.

Another development which is being used by the navigators flying the Atlantic is the radio compa.s.s. This instrument may be turned toward a land or sea wireless station, of which the call is known, and it will register the bearing from the flying-boat to this station. It may be turned upon another station, and this bearing also charted. The intersection of these two wireless compa.s.s bearings gives the position of the s.h.i.+p at sea. The radio compa.s.s is dependable day or night, and is said to be quite as reliable as a s.e.xtant or other navigating instruments.

Sailmakers to repair airplane fabrics, to sew new covers for planes--these men must find an opportunity in flying. There are literally thousands of wings, as yet unmade, which will carry the air traffic of the future. It matters not whether men or women take up this branch of the work, it must be done, and done with a conscience.

Like all other branches of the mechanical maintenance of an airplane, careless work on the part of a sailmaker may mean disaster for the pilot. One of the latest fatalities at a Long Island flying-field was due to careless st.i.tching, or weakness of fabric, which gave way under great pressure due to high speed. The linen cover of an upper plane ripped off at a height of one hundred and fifty feet, and the pilot was killed in the fall of the machine.

Photographers may yet take the place of surveyors, or work hand in hand with them in the making of aerial maps of the country. The map of the future must be an aerial map, a mosaic map such as was used by our army headquarters. Nothing can exceed the eye of the camera for accuracy. Cameras bolted to airplanes, such as were used by our army for reconnaissance, have already been used for mapping cities. The mapping of the entire country in such a manner is only a matter of time.

One thing which an aviation mechanic of any sort must bear in mind is that he _must_ do his work with a conscience. True, he is handling mute metal engines, or dumb wires and struts--but in his work he holds the life of the pilot in his hand. It is not too much to say that hundreds of pilots' lives have been saved by the conscientious work of skilled mechanics who realized the danger of the air.

I have seen mechanics rush from a hangar in a frenzy of excitement and agitation. ”That machine must not go up; it has been repaired, but not inspected!” They have done their work with a will in the army; they have learned some of the dangers of flying and weak spots which must be watched. The civilian mechanic must be taught many things.

First of all he must know the value of inspection. Every machine which has gone through a workshop must be inspected and checked over by a skilled mechanic before a pilot is allowed to fly it. The ideal thing would be to have legislation licensing the inspectors of aircraft and requiring that repairs on all machines be examined by a licensed inspector. The inspectors would be under civil service and would be selected by compet.i.tive examination. It may sound fantastic, but such precautions are as necessary for the preservation of life as legislation on sanitary matters.

In the second place, there should be time limits placed by law covering the period of usefulness of various parts of an airplane.

After fifty hours of flying there should be an inspection of certain working parts of the engine, certain wires in the body which may be strained by bad landings, and other wires in the rigging strained by flying in bad weather. New wires are always sagging and stretching a bit. Wings will ”wash out,” lose their usefulness by excessive flying, and must be replaced. There is a great volume of data on these matters which should be the basis for laws covering mechanical inspection of airplanes, and with which the airplane mechanic must become familiar.

For the man who would like to work into the piloting of aircraft there is a very good opportunity by starting with the mechanical side. Too many pilots know next to nothing about the construction of their machines. When an engine goes bad they know that it won't run--that is all. The pilot who is a good mechanic is a gifted man in his profession.

There are endless opportunities at flying-fields for mechanics who want to learn to fly. During the war it became customary to take mechanics up for flying at least once in two weeks on some fields. It gave the mechanic an interest in his work and an interest in the life of his pilot. Perhaps nothing stimulated accurate work by a mechanic more than the knowledge that at any time he might be called upon to ride in one of the planes he had helped make or repair.